Film cassette and method of making the same

Abstract

A novel film cartridge, camera for use with such cartridge and method of making such cartridge are disclosed. The cartridge is in form of a pocket of a material which is impermeable to light and which accommodates a multi-exposure film strip having a length at least equal to the length of the pocket. The pocket is provided with at least one opening extending transversely to its elongation and through which a leading end of the film strip extends to the exterior of the pocket so that it can be engaged by a film transporting mechanism of a camera suitable for accommodating such a pocket, which mechanism transports the film strip either in one continuous movement out of the pocket and into a storage space of the camera from where it is sequentially transported into the pocket in increments during which exposures are made, or else the film is sequentially transported out of the pocket and into the camera storage space with exposures being made during each transporting step and the exposed film is thereupon returned in a single movement into the pocket. However, the pocket may also have two parts one of which accommodates the non-exposed film strip which is then transported during exposures into the other part so that the film strip becomes completely located in the other part when it is fully exposed and a re-transportation into the first part of the pocket is not necessary. Cameras suitable for use with various embodiments of the novel cartridge are also disclosed, as well as methods of making the cartridge.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims: 
     
       1. A film cassette for a multi-exposure film strip, comprising a light-impermeable elongated flat pocket having a length corresponding at least to the length of a film strip to be accommodated therewithin and being provided with at least one opening extending transverse to the elongation of the pocket for passage of the film strip therethrough; means for sealing the opening against the entry of light into the pocket; said pocket having two major walls in part bounding said compartment; spacing means in said compartment for preventing said major walls from moving into contact with one another and thus blocking said compartment; said spacing means comprising spacing elements located in said compartment laterally of the path of film strip movement therethrough; and wherein said spacing elements are lateral guides for longitudinally extending edge portions of the film strip. 
     
     
       2. A film cassette for a multi-exposure film strip, comprising a light-impermeable elongated flat pocket having a length corresponding at least to the length of a film strip to be accommodated therewithin and being provided with at least one opening extending transverse to the elongation of the pocket for passage of the film strip therethrough; means for sealing the opening against the entry of light into the pocket; said pocket having two major walls in part bounding said compartment; spacing means in said compartment for preventing said major walls from moving into contact with one another and thus blocking said compartment; said spacing means comprising an insert which is installed in said compartment. 
     
     
       3. A film cassette as defined in claim 2, wherein said pocket is flexible. 
     
     
       4. A film cassette as defined in claim 2, wherein said pocket has grooves or folds extending across it in direction normal to the pocket elongation. 
     
     
       5. A film cassette as defined in claim 2, said spacing means further comprising spacing elements located in said compartment laterally of the path of film strip movement therethrough. 
     
     
       6. A film cassette as defined in claim 2, said compartment constituting at least substantially in the region for accommodating the film strip the neutral line for flexing of the pocket in direction transverse to the elongation thereof. 
     
     
       7. A film cassette as defined in claim 2, and further comprising a bending-resistant member embracing said pocket at least in part and preventing spreading-apart of said opening for the film strip. 
     
     
       8. A film cassette as defined in claim 2, wherein a portion of the film strip extends out of said pocket through said opening, said portion being opaque to light. 
     
     
       9. A film cassette as defined in claim 8, wherein said portion is provided with a film perforation hole. 
     
     
       10. A film cassette as defined in claim 2, said film strip having a portion extending from said pocket out through said opening; and further comprising at least one perforation hole in said portion for engagement by the film transporting mechanism of a camera. 
     
     
       11. A film cassette as defined in claim 10, wherein said perforation hole is located on a line constituting an extension of a row of film transporting perforations in the film strip. 
     
     
       12. A film cassette as defined in claim 2, wherein the film strip has a leading end extending out through said opening, and a trailing end; and further comprising cooperating retaining portions on said trailing end and on said pocket adjacent said opening for preventing withdrawal of said trailing end from said opening. 
     
     
       13. A film cassette as defined in claim 12, said retaining portions including a bead on said trailing end of a width which is greater than the width of said opening. 
     
     
       14. A film cassette as defined in claim 10, said camera having spaced ends; and further comprising means at one of said ends for arresting the pocket in a camera against movement relative to the camera. 
     
     
       15. A film cassette as defined in claim 14, said arresting means comprising a recess adapted to cooperate with a projection of a camera. 
     
     
       16. A film cassette for a multi-exposure film strip, comprising a light-impermeable elongated flat pocket having a length corresponding at least to the length of a film strip to be accommodated therewithin and being provided with at least one opening extending transverse to the elongation of the pocket for passage of the film strip therethrough; and means for sealing the opening against the entry of light into the pocket; said pocket having two major walls in part bounding said compartment; spacing means in said compartment for preventing said major walls from moving into contact with one another and thus blocking said compartment; said spacing means comprising spacing elements located at opposite sides of the path of film strip movement, and a web connecting said spacing elements and extending parallel to the general plane of said pocket. 
     
     
       17. A film cassette for a multi-exposure film strip, comprising a light-impermeable elongated flat pocket having a length corresponding at least to the length of a film strip to be accommodated therewithin and being provided with at least one opening extending transverse to the elongation of the pocket for passage of the film strip therethrough; and means for sealing the opening against the entry of light into the pocket; said pocket having two major walls in part bounding said compartment; spacing means in said compartment for preventing said major walls from moving into contact with one another and thus blocking said compartment; said spacing means comprising spacing elements arranged along the elongation of said pocket and provided with grooves to enhance the ability of said spacing elements to bend when the pocket is inserted in non-straight condition into a camera. 
     
     
       18. A film cassette as defined in claim 17, wherein said grooves are of trapezoidal or of triangular cross-section. 
     
     
       19. A film cassette for a multi-exposure film strip, comprising a light-impermeable elongated flat pocket having a length corresponding at least to the length of a film strip to be accommodated therewithin and being provided with at least one opening extending transverse to the elongation of the pocket for passage of the film strip therethrough; and means for sealing the opening against the entry of light into the pocket; said pocket having two major walls in part bounding said compartment; spacing means in said compartment for preventing said major walls from moving into contact with one another and thus blocking said compartment; said pocket having major walls provided with inner surfaces bounding said compartment; and wherein said spacing means comprises spacing elements provided on at least one of said inner surfaces. 
     
     
       20. A film cassette as defined in claim 19, wherein said spacing elements are of one piece with the wall having said one inner surface. 
     
     
       21. A film cassette for a multi-exposure film strip, comprising a light-impermeable elongated flat pocket having a length corresponding at least to the length of a film strip to be accommodated therewithin and being provided with at least one opening extending transverse to the elongation of the pocket for passage of the film strip therethrough; and means for sealing the opening against the entry of light into the pocket; said pocket having two major walls in part bounding said compartment; spacing means in said compartment for preventing said major walls from moving into contact with one another and thus blocking said compartment; said spacing means comprising spacing elements located at opposite sides of the path of film strip movement, said spacing elements being inclined towards one another transversely of the elongation of said pocket and the major distance between them being larger than the film strip width whereas the minor distance between them is smaller than the film strip width, so that said elements each define a film strip guiding groove of substantially triangular cross-section extending lengthwise of the pocket. 
     
     
       22. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; said compartment constituting at least substantially in the region for accommodating the film strip the neutral line for flexing of the pocket in direction transverse to the elongation thereof; and a glide strip having a width equal to at least a part of the film strip width and having one end connected to said pocket at said opening and another end located in said compartment spaced lengthwise from said one end. 
     
     
       23. A film cassette as defined in claim 22, said pocket having two major sides provided with transversely extending grooves or folds, and said opening being bounded by two edges to one of which said glide strip is secured to overlie the grooves or folds in one of said major sides; and further comprising another glide strip similar to the first-mentioned one and secured to the other of said two edges to overlie the grooves or folds in the other of said major sides. 
     
     
       24. A film cassette for multi-exposure film strips, comprising a flat elongated pocket or opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; said compartment constituting at least substantially in the region for accommodating the film strip the neutral line for flexing of the pocket in direction transverse to the elongation thereof; and wherein said pocket has two flat major walls which are provided with bellows folds at opposite sides of said neutral line. 
     
     
       25. A film cassette as defined in claim 24, said pocket also having two longitudinally extending minor walls, and said folds being provided in said minor walls also. 
     
     
       26. A film cassette as defined in claim 24, said opening having two longitudinal edges; and further comprising glide strips secured to the respective edges and having a width at least equal to part of the length of said edges, said glide strips overlying said folds and extending lengthwise of said pocket at opposite sides of said neutral line and having free ends located but unsecured in said compartment. 
     
     
       27. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough said pocket having two major walls which are adapted for slight convex bulging in direction outwardly of said compartment. 
     
     
       28. A film cassette as defined in claim 24, wherein one of said major walls bulges transversely to the elongation of the pocket to a greater extent than the other wall, and wherein said other wall has limited extensibility transverse to said elongation. 
     
     
       29. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; said opening being bounded by lips which sealingly engage a portion of the film strip to prevent the entry of light into said compartment; and means for maintaining said lips in such sealing engagement. 
     
     
       30. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; and further comprising sealing strips at said opening for engagement with the film strip so as to prevent the entry of light into said compartment. 
     
     
       31. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; a portion of the film strip extending out of said pocket through said opening; and further comprising a cap surrounding a section of said pocket which is provided with said opening so as to prevent the entry of light into said opening, said cap being connected to said portion of the film strip. 
     
     
       32. A film cassette as defined in claim 31, said cap having two major sides and two minor sides and being constructed so as to be squeezable at said two minor sides in direction normal to the planes of said major sides. 
     
     
       33. A film cassette as defined in claim 32, wherein said minor sides are provided with folds. 
     
     
       34. A film cassette as defined in claim 31, wherein said cap includes sealing means for preventing the access of light to said opening. 
     
     
       35. A film cassette as defined in claim 34, wherein said sealing means comprises a labyrinth seal which overlaps the edges of said opening in the pocket. 
     
     
       36. A film cassette as defined in claim 34, said sealing means including a sealing strip provided at an inner edge of said cap and bevelled in direction towards said pocket. 
     
     
       37. A film cassette as defined in claim 31; and further comprising means for preventing unintentional withdrawal of said cap and/or film strip from said pocket. 
     
     
       38. A film cassette as defined in claim 37, said preventing means comprising a friction fit between said cap and said pocket. 
     
     
       39. A film cassette as defined in claim 37, said preventing means comprising an adhesive strip adhered to said pocket and to one of said cap and film strip, respectively. 
     
     
       40. A film cassette as defined in claim 39, said adhesive strip having a weakened zone designed to tear when subjected to stress. 
     
     
       41. A film cassette as defined in claim 37, said preventing means comprising at least one projection on one of said pocket and cap, and at least one cooperating recess on the other of said pocket and cap, said projection being disengageable from said recess by an element of a camera in which said pocket is used. 
     
     
       42. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; the film strip having a leading end extending out through said opening, a trailing end and retaining portions on said trailing end and on said pocket adjacent said opening for preventing withdrawal of said trailing end from said opening; said retaining portions comprising a hole in said trailing end of the film strip, and a tooth on said pocket having a steep flank facing counter to the direction of film strip movement out of said opening and a subsequent inclined surface. 
     
     
       43. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; said pocket having a length substantially equal to twice the length of said film strip, and said opening being in form of two slots spaced lengthwise of the pocket by a distance corresponding substantially to the width of a film frame and defining between themselves an exposure window, so that the film strip can be sequentially transported out of said pocket through one of said slots, exposed in the window intermediate the slots and transported back into the pocket through the other slot. 
     
     
       44. A film cassette as defined in claim 43, said film strip having a leading end provided with a leader and a trailing end provided with a trailer which are located in said exposure window prior and subsequent to the first and last exposure, respectively. 
     
     
       45. A film cassette as defined in claim 44; and further comprising transverse folds in said pocket adjacent said film window so as to facilitate folding of the pocket back upon itself. 
     
     
       46. A film cassette as defined in claim 44, said leader and said trailer being provided with respective perforations. 
     
     
       47. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; said camera hving spaced ends; and further comprising means at one of said ends for arresting the pocket in a camera against movement relative to the camera, said arresting means comprising an eyelet on said pocket. 
     
     
       48. A film cassette for multi-exposure film strips, comprising a flat elongated pocket of opaque material having an inner compartment for a film strip and being of a length at least equal to the length of the film strip; at least one opening provided in said pocket and extending normal to the elongation thereof for passage of the film strip therethrough; said camera having spaced ends; and further comprising means at one of said ends for arresting the pocket in a camera against movement relative to the camera, said arresting means comprising a bead adapted to be inserted into a retainer of a camera. 
     
     
       49. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip, comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; and wherein said cassette chamber is arcuately curved in its longitudinal direction. 
     
     
       50. A camera as defined in claim 49; further comprising a lens and a film window located on an optical axis; and wherein said cassette chamber and said storage chamber are located at opposite sides of said optical axis. 
     
     
       51. A camera as defined in claim 49, said cassette chamber being shaped to accommodate the pocket in a non-planar condition; and further comprising means for holding the pocket in said non-planar condition. 
     
     
       52. A camera as defined in claim 49, said cassette chamber being in part formed as a duct into which the pocket is partially lengthwise insertable. 
     
     
       53. A camera as defined in claim 52, the pocket having a closed end and another end provided with said opening, and wherein said duct is dimensioned to receive said closed end. 
     
     
       54. A camera as defined in claim 52; further comprising means in said duct for retaining the inserted pocket therein. 
     
     
       55. A camera as defined in claim 49; and further comprising means for arresting the pocket in said cassette chamber against movement relative thereto. 
     
     
       56. A camera as defined in claim 49, said film transporting means including means for engaging a leading end of the film strip which extends out of the pocket through said opening. 
     
     
       57. A camera as defined in claim 49, said film transporting means being engageable with a perforation formed in a leading film strip end which extends out of the pocket through said opening. 
     
     
       58. A camera as defined in claim 49; further comprising a film spool mounted for rotation in said storage chamber and with which a leading end of the film strip is connectable; and wherein said film transporting means are operative for rotating said spool. 
     
     
       59. A camera as defined in claim 49, said film transporting means comprising a sprocket wheel engageable with perforations of the film strip. 
     
     
       60. A camera as defined in claim 49, said film transporting means comprising a film engaging element, and a spring motor which is tensioned when said element transports the film strip in a first direction into said storage chamber and is successively released to dissipate its stored energy for incremental return of the film strip in a second direction into the pocket during each operation of a shutter of the camera. 
     
     
       61. A camera as defined in claim 60; further comprising abutments cooperating with said element and said spring motor for limiting the extent of film strip transport in the respective directions. 
     
     
       62. A camera as defined in claim 60; and further comprising a film frame counter operative to count film frames in response to movement of the film strip. 
     
     
       63. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; said cassette chamber being in part formed as a duct into which the pocket is partially lengthwise insertable; means in said duct for retaining the inserted pocket therein; said retaining means comprising pocket-retaining springs in said duct. 
     
     
       64. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; means for arresting the pocket in said cassette chamber against movement relative thereto, said arresting means comprising a hook on the camera for engagement in an eyelet of the pocket. 
     
     
       65. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; means for arresting the pocket in said cassette chamber against movement relative thereto, said arresting means comprising a groove in the camera adapted to receive a bead on the pocket. 
     
     
       66. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; means for arresting the pocket in said cassette chamber against movement relative thereto, said arresting means comprising a projection on the camera and adapted to engage in a recess of the pocket. 
     
     
       67. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; said film transporting means including means for engaging a leading end of the film strip which extends out of the pocket through said opening; said engaging means comprising a hook engageable in a perforation of the leading end. 
     
     
       68. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip, comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; and film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket, said film transporting means comprising a film gripper. 
     
     
       69. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip, comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; and film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket, the pocket having an exposure window at which the film strip is incrementally located outside the pocket; and further comprising means for arresting the pocket in the camera so that the exposure window registers with a film window of the camera. 
     
     
       70. A camera as defined in claim 69, said arresting means comprising guide rails for the pocket and/or pins engageable in locating holes of the pocket. 
     
     
       71. A camera as defined in claim 69, wherein sections of the pocket become located at opposite sides of the film window, said cassette chamber and said storage chamber each accommodating one of said sections in form of at least one arcuate loop. 
     
     
       72. A camera as defined in claim 69, the film strip having a leader and a trailer and the film strip, the leader and the trailer all having film perforations; and wherein said film transporting means cooperate with said film perforations in the region of said exposure window. 
     
     
       73. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip, comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; and wherein the film strip has one perforation for each film frame; said film transporting means including a turnable sprocket wheel having teeth spaced from one another at such angular distances that turning of the wheel by an increment corresponding to the distance from one to the next tooth advances the film strip by one film frame. 
     
     
       74. A photographic camera for use with a film-strip cassette in form of an elongated pocket having a transverse opening for extraction and return of the film strip, comprising means forming an elongated cassette chamber; means forming a storage chamber for film strip extracted from the cassette; film transporting means for extracting the film strip from the pocket and transporting it into the storage chamber, and for subsequently returning the film strip into the pocket; and said exposure window being provided in a major surface of the pocket; and further comprising blocking means on said pocket and operative for respectively exposing and light-tightly closing said exposure window. 
     
     
       75. A camera as defined in claim 74, said pocket also having a longitudinal slot extending lengthwise of the pocket opposite a line of perforations in the film strip and through which the film transporting mechanism engages the perforations, said blocking means also respectively exposing and closing said slot. 
     
     
       76. A camera as defined in claim 74, wherein the pocket has an additional exposure window in another major surface opposite the first-mentioned surface, said exposure windows being at least substantially in register with one another and said blocking means exposing and closing both of said windows. 
     
     
       77. A camera as defined in claim 74, said exposure window being located near one end of said pocket at which said opening is provided. 
     
     
       78. A camera as defined in claim 74, said blocking means comprising a slide which light-sealingly embraces the pocket and which in the direction of elongation of the pocket has a length which is at least equal to the length of said exposure window in said direction. 
     
     
       79. A camera as defined in claim 78, wherein said slide is a circumferentially complete bracket surrounding the pocket. 
     
     
       80. A camera as defined in claim 78, wherein said slide is substantially C-shaped and overlies said major surface, lateral minor surfaces and parts of another major surface of the pocket which parallels the first-mentioned major surface. 
     
     
       81. A camera as defined in claim 78, said slide having at least one projection extending beyond the pocket for engagement by an element of the camera. 
     
     
       82. A camera as defined in claim 81, said projection being formed by at least one exterior dimension of the slide being greater than the corresponding exterior dimension of the pocket. 
     
     
       83. A camera as defined in claim 78; and further comprising means for retaining said slide against unintended movement out of the position in which it closes said window. 
     
     
       84. A camera as defined in claim 78, said slide having friction contact with said pocket to prevent unintended movement of the slide out of the position in which it closes said window. 
     
     
       85. A camera as defined in claim 78, said slide being of elastically yieldable material and engaging said pocket with pretension, so as to be prevented from unintended movement out of its position in which it closes said window. 
     
     
       86. A camera as defined in claim 74, said blocking means comprising a slide in said pocket interposed and slidable between the film strip and a wall of the pocket having said major surface. 
     
     
       87. A camera as defined in claim 86, said slide including a projection extending out of said pocket and beyond said major surface through a slot in the pocket. 
     
     
       88. A camera as defined in claim 74, said blocking means comprising a rotatable disk. 
     
     
       89. A camera as defined in claim 88, said disk being mounted in said pocket between the film strip and a wall of the pocket which has said major surface. 
     
     
       90. A camera as defined in claim 89, said disk including a projection which extends out of said pocket. 
     
     
       91. A camera as defined in claim 90; further comprising means for preventing unintended turning of the disk to a position in which it exposes said window. 
     
     
       92. A camera as defined in claim 91, said preventing means being a retarding spring. 
     
     
       93. A camera as defined in claim 90, said preventing means including an engaging portion on said disk which cooperates with a camera portion when said disk is in a position in which it closes said opening. 
     
     
       94. A camera as defined in claim 90, said disk being of circular shape and including means journalling it for rotation about an axis proximal to a corner of said window; said pocket having a wall provided with said major surface and with an arcuate slot which merges with said window and in which said projection is movable. 
     
     
       95. A camera as defined in claim 74; and further comprising actuating means engageable with said blocking means and operative for moving the blocking means to at least one of the positions in which it exposes and closes said window, respectively. 
     
     
       96. A camera as defined in claim 95, said blocking means having at least one engaging portion, and said actuating means having at least one engaging element engageable with said engaging portion in response to insertion or removal of the pocket from the camera, respectively. 
     
     
       97. A camera as defined in claim 96, said cassette chamber being a duct dimensioned to accommodate said pocket and engaging portion on endwise insertion of the pocket; and said engaging element being a constriction formed in the duct ahead of the optical axis of the camera, so that insertion of the pocket past said constriction results in shifting of said blocking means relative to the pocket to a position in which it exposes said window. 
     
     
       98. A camera as defined in claim 97; and further comprising a spring-biased element extending into said duct and operative for engaging and returning said blocking means to the window closing position thereof, in response to movement of the pocket out of said duct. 
     
     
       99. A camera as defined in claim 74, said camera having a cover movable between an open and a closed position; and further comprising means for moving said blocking means to window exposing position in response to movement of said camera cover to said closed position, and vice versa. 
     
     
       100. A camera as defined in claim 99, said camera cover being slidable between said open and closed positions. 
     
     
       101. A camera as defined in claim 99, said camera cover having a part which is pivotable and slidable, and said means for moving being provided in said part. 
     
     
       102. A camera as defined in claim 101, said means for moving comprising claws which are disengaged from said blocking means when said part of said cover is in an unlatched portion thereof, and which engage and move said blocking means during movement of said part to latched position. 
     
     
       103. A film cassette, comprising an elongated frame of U-shaped cross-section having at least one flat side; light-impeameable means forming a pocket adapted to contain a multi-exposure film strip and including a portion covering at least said one flat side; and a film opening in said pocket extending transverse to the elongation thereof. 
     
     
       104. A film cassette as defined in claim 103, said frame also having three narrow sides one of which is open and being provided with a film guide groove which extends from said one narrow side to another opposite narrow side. 
     
     
       105. A method of making a film cassette, comprising the steps of providing an elongated frame having substantially U-shaped cross-section; feeding an opaque material having a width corresponding to substantially the length of the frame, towards the frame in a direction normal to the elongation of the frame; and sealingly connecting the material about the frame so as to form with the frame a pocket the interior of which is sealed against the entry of light. 
     
     
       106. A method as defined in claim 105, wherein the step of feeding comprises advancing the material as a web, and severing from the web sections of a size requisite for forming the respective pocket. 
     
     
       107. A method as defined in claim 106; and further comprising the step of inserting a strip of light-sensitive film into the frame in direction lengthwise of the same and normal to the feeding direction of the web. 
     
     
       108. A method as defined in claim 107, the step of connecting comprising aligning one longitudinal edge of the frame with a longitudinal edge of the material, connecting the frame and material at said edges, and thereupon carrying out the step of inserting the film strip. 
     
     
       109. A method as defined in claim 107, wherein the film strip is fed towards the frame in a plane parallel to the web, and wherein the frame is placed onto the material and the film strip in direction normal to the feeding directions of the web and film strip, so as to straddle and surround the film strip on three sides thereof. 
     
     
       110. A method as defined in claim 109, wherein the severed web section is folded about a narrow longitudinal side and about a upper side of the frame and is then light-tightly connected with surfaces of the frame which extend parallel to the plane of the film strip. 
     
     
       111. A method as defined in claim 110, wherein the step of connecting is effected by adhesive bonding. 
     
     
       112. A method as defined in claim 110, wherein the step of connecting is effected by heat-welding. 
     
     
       113. A method as defined in claim 105, wherein the frame has an open side, and the step of connecting comprises sealing said material over said open side. 
     
     
       114. A method as defined in claim 105, the frame having two ends at least one of which is open and constitutes an opening for later extraction of a film strip from the pocket; and further comprising the step of installing light-seals at said open end prior to connecting of said frame and material.